Emodin Inhibits Breast Cancer Cell Proliferation through the ERα-MAPK/Akt-Cyclin D1/Bcl-2 Signaling Pathway

Background: The aim of the present study was to investigate the involvement of emodin on the growth of human breast cancer MCF-7 and MDA-MB-231 cells and the estrogen (E2) signal pathway in vitro. Materials and
Methods: MTT assays were used to detect the effects of emodin on E2 induced proliferation of MCF-7and MDA-MB-231 cells. Flow cytometry (FCM) was applied to determine the effect of emodin on E2-induced apoptosis of MCF-7 cells. Western blotting allowed detection of the effects of emodin on the expression of estrogen receptor α, cyclin D1 and B-cell lymphoma-2 (Bcl-2), mitogen-activated protein kinases (MAPK) and phosphatidylinostiol 3-kinases (PI3K). Luciferase assays were emplyed to assess transcriptional activity of ERα.
Results: Emodin could inhibit E2-induced MCF-7 cell proliferation and anti-apoptosis effects, and arrest thecell cycle in G0/G1 phase, further blocking the effect of E2 on expression and transcriptional activity of ERα. Moreover, Emodin influenced the ER α genomic pathway via downregulation of cyclin D1 and Bcl-2 protein expression, and influenced the non-genomic pathway via decreased PI3K/Akt protein expression.
Conclusions: These findings indicate that emodin exerts inhibitory effects on MCF-7 cell proliferation via inhibiting both non-genomic and genomic pathways.